Validation of several sets of delayed-neutron group parameters for thermal fission of ²³⁵U by a Feynman-α analysis

ABSTRACT

Time-sequence count data of a neutron counter were acquired at subcritical states of UTR-KINKI reactor and then a Feynman-α analysis considering delayed neutrons was carried out to determine a measured ratio of delayed to prompt neutron contribution to the correlation amplitude Y. The zero-power reactor was driven by a neutron source inherent in highly enriched uranium fuels to reduce any spatial effect. The delayed-to-prompt ratio was also calculated using several sets of delayed-neutron group parameters for thermal fission of ²³⁵U nuclide, to validate these sets by comparing with the measured ratio. The ratios calculated using Keepin’s 6-group and Spriggs’ 8-group sets agreed very well with the measured ratio. However, the ratios calculated using the other sets were almost the same as each other and in a very poor agreement with the measured ratio.

KEYWORDS:

• UTR
• Feynman-α
• delayed neutron
• validation
• group parameters
• Keepin
• MVP

Disclosure statement

No potential conflict of interest was reported by the author(s).